Over the past several years, the development of office furniture increasingly has been directed to modular units in the form of preassembled integral components. These components then are fitted together to provide work areas, storage spaces and partial room dividers for separating the work areas of different employees. Modular units are popular because they result in maximum efficiency in the utilization of a work space and permit a wide variety of arrangements to accomodate a correspondingly wide variety of work environments. As departments grow (or shrink) in size, additional units or rearrangement of units is readily accomplished without major construction or reconstruction which otherwise would be required for offices with fixed partitions.
In the development of modular office furniture, the integrated units often include a lower work area or desk area constructed with an upper storage area for books, papers, or the like. The upper area sometimes includes what is known as a "task light" fixture built into it for the purpose of illuminating the desk or work area below.
Generally, task light fixtures use fluorescent light bulbs in various arrangements to provide the desired illumination. Fluorescent bulb fixtures are desirable for a number of reasons. Fluorescent lamps use less energy for a given light output and run substantially cooler in temperature than conventional incandescent bulbs. In addition, fluorescent fixtures generally are shallower than incandescent fixtures. This is particularly desirable for a modular office work area system; so that the light fixture does not occupy space which otherwise can be used for bookshelves, storage, or the like, in the upper portion of the unit.
To minimize glare, both directly from the fixtures and from the work area below, it has been found desirable to place fixtures on the left and right sides of the work area in preference to a fixture which is located directly above the primary work area of the desk or table beneath it. Consequently, it is common to use two task lamp or task light fixtures on opposite sides of the work area. Direct glare from the fixtures is eliminated by having baffles, shields, or the like, extending downwardly from the fixture to cut off direct view of the bulbs in the fixture from a person sitting at the work area. To eliminate light and dark zones from the fixture projected onto the work area, it generally has been a practice to place diffuser plates or lenses over the fixture to spread the light emanating from it onto the work area. Diffuser plates, while they do accomplish the purpose of spreading the light, result in a reduction in the overall efficiency of the light output from the fixture.
Another disadvantage which occurs with task light fixtures placed above opposite ends of the work area is that such fixtures provide the best illumination of the area immediately below the fixture, with the illumination diminishing in the center of the work area. It is in the center of the work area, however, where concentration of the light should be, since this generally is the area of a modular unit in an office system where most of the work is done by a person using the module.
Task light systems of the prior art which have been developed for illuminating a work area below the fixture are disclosed in the patents to Shemitz, U.S. Pat. No. 4,054,793, issued Oct. 18, 1977, and Benasutti et al., U.S. Pat. No. 4,161,767, issued July 17, 1979. The Benasutti patent is directed to a task light which utilizes a pair of relatively wide-legged, U-shaped fluorescent bulbs mounted in a flat fixture above a work area. No concentration of light coming from the opposite sides of the work area is accomplished, and the fixture primarily relies upon direct lighting from the bulbs onto the work area below.
The Shemitz patent discloses a task light using a single fluorescent bulb extending across the width of the work area. The light from the fixture is directed from the rear of the work area onto it; and because of the orientation of the bulb, can result in light being reflected from the work area into the eyes of a person sitting at that area.
Two other patents which disclose light fixtures for illuminating a surface below the fixture are the patents to Doane, U.S. Pat. No. 2,240,179, issued Apr. 29, 1941, and U.S. Pat. No. 2,560,281, issued July 10, 1951. The Doane '179 patent is a symmetrical fixture using stacked fluorescent bulbs for spreading the light beneath the fixture uniformly. This patent does not disclose a fixture which is intended to concentrate the light off to one side of the fixture.
The Doane '281 patent is directed to a fixture for projecting the light emanating from it off to one side of the fixture. The arrangement of the bulbs and the configuration of the reflector in this fixture, however, results in considerable loss of light reflected back into the fluorescent bulbs, and, in addition, the fixture employs movable shields which will tend to block some of the light from the fixture, further reducing its efficiency.
It is desirable to provide a task light fixture which has maximum efficiency in terms of light output for the energy consumed by the fixture, as well as which concentrates the light at the center of the work area, where it is most needed, without reflection into the eyes of the person sitting or standing at the work area. In addition, it is desirable to provide such a fixture which overcomes the disadvantages of the prior art fixtures described above.